Panels widely referred to as “sandwich panels” are known in the art and used in particular for cladding ceilings and/or walls in passenger aircraft cabins. Such a sandwich panel consists of a lightweight core, which is laminated on both sides with a cover layer. The core comprises a honeycomb structure formed by a large number of walls. These cell walls are manufactured from a fiber paper impregnated with phenol resin, but other materials such as cardboard, plastics material, etc. can also be used. The cover layer usually consists of a fibrous material or fabric impregnated with resin. To produce the sandwich panel, the two opening planes of the honeycomb board are each covered with a semi-finished product or prepreg, which is formed from a fibrous material or fabric impregnated with resin. The semi-finished product is laminated together with the honeycomb board under the effect of pressure and temperature. The selected pressure for this process is such that the honeycomb structure of the board is maintained fully.
Sandwich panels are lightweight and have relatively poor sound-absorbing properties. In order to increase flight comfort, the sound-absorbing properties of traditional sandwich panels are no longer regarded as adequate. To improve sound insulation, the current practice is to insert a layer of silicon film and/or glass wool on the rear side of the cabin wall or ceiling and on the sandwich panel. Although this improves sound insulation, it simultaneously detrimentally increases the weight of the aircraft.
DE 23 02 989 A describes a method for bending a sandwich board, in which the sandwich board comprises cover layers made from sheet metal and a core that is rigidly connected to these layers, said board being bent while simultaneously crushing the core until the required bending angle is achieved. Further prior art is described in FR 1 260 187 A, U.S. Pat. No. 3,687,767 A, U.S. Pat. No. 3,412,513 A and DE 18 16 894 U.